masterTable.all(`SELECT ledger_num,file_num,client_name,vehicle_number,vehicle_model,registered_on FROM masterTable` , (err,data) => {
    w = getPureArray2d(data)
    reminderTable.all(`SELECT reminder_created_on ,upcoming_reminder_date , last_reminder_message ,status FROM reminderTable` , (err,data2) => {
      x = getPureArray2d(data2)
      updatesTable.all(`SELECT total_balance ,last_paid_date FROM updatesTable` , (err,data3) => {
        y = getPureArray2d(data3)
        masterTable.all(`SELECT phone_number1 ,phone_number2 ,phone_number3 agreementEx, permitEx  FROM masterTable` , (err,data4) => {
          z = getPureArray2d(data4)
          event.reply('gotAllDataForMasterTable', unionOnColumns(unionOnColumns(unionOnColumns(w,x),y),z))
        })
      })
    })
  })

I am trying to merge data from multiple data base into a single array , this is to create a table in my electron app and , the number of rows in all the data base are the same so I am bringing them in and the merging them with a function

I am using a separate function to perform union

function unionOnColumns(first,second) {
  var mergeOnRows = second.map((item, i) => {
      return [...first[i], ...item];
  });
  return mergeOnRows
}

this seems like a really stupid way... so is there a better way of getting data from multiple database and merging them into a single array